The present disclosure relates to power filtering circuits, and more specifically, to integration of an inductor and damper for a power filtering circuit.
A basic building block of a power filter is a low pass filter including an inductor (L) and a capacitor (C). This filter can also contain a damper circuit including a capacitor and a damper resistor (R). Prior art damper resistors use off-the-shelf resistors that may be either thick film or metal foil resistors. Resistor failures have been a leading cause for failures of various motor controllers during production processes. The prime causes of resistor failures are due to the fragile ceramic base and low pulse power capability of the resistor element.
Conventional wire wound resistors are generally large and bulky. A package style that includes separate wire wound resistors would require a wire harness and supports that increase production time and cost significantly, and also may reduce overall reliability. Additionally, a cold plate may be needed to provide a heat drain path from a printed wiring board mounted resistor element as the damper resistor.